Παραπομπή σε μορφή APA (7η εκδ.)

Hultgren, T. (1942). Railway freight traffic in prosperity and depression. National Bureau of Economic Research.

Παραπομπή σε μορφή Chicago (17η εκδ.)

Hultgren, Thor. Railway Freight Traffic in Prosperity and Depression. New York: National Bureau of Economic Research, 1942.

Παραπομπή σε μορφή MLA (9th εκδ.)

Hultgren, Thor. Railway Freight Traffic in Prosperity and Depression. National Bureau of Economic Research, 1942.